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Wed Jun 18, 2025 9:24 am

Greetings,

I've had a couple responses to my other topics in which it was recommended to replace the existing exhaust on my recently acquired 1969 Dune Buggy.

Engine:
H 5692428
88 Kit - Stroke 76mm
Carburetor - 34PIC T-3
Dual Port

I've been searching the internet and there are so many exhaust variations and no real way to tell what they sound like. I'm hoping I can get some suggestions based on first hand experience.

Preferences:

- A little quieter exhaust if possible
- Chrome/Ceramic Coated would be awesome

Pics of my existing exhaust which has a baffle insert and blanks on the heat risers.

(there is no blank on the heat riser in this pic. They were installed after the pic was taken)

Many thanks !

Wed Jun 18, 2025 9:52 am

You have what is the worst system you can have.

A 1-1/2" system would be best but since it's in a dune buggy this topic might be better off in the Dune Buggy forum.

PM me if you want it moved... please don't just start another.

Wed Jun 18, 2025 10:20 am

Tri-mil or AA offers some decent buggy/baja type exhausts. You arent going to find something by searching based on sound. Too many variables. Making a custom muffler is easy, cheap if what you buy, you dont like

Like glenn said, your present setup is poor at best.

This is a magnaflow muff i built. Not loud at all, good performance

Wed Jun 18, 2025 1:22 pm

As I mentioned, multiple people have commented on the quality of my current exhaust, but nobody has mentioned why it is so bad. Could somebody tell me why it is so bad? That would help to ensure that I don't buy a replacement exhaust that is just as bad.

Should i be looking for a separate exhaust for left and right, or is the type where all four join into one pipe and then goes through a muffler a better choice?

So far I have gathered that I should use an 1 1/2 system.

I appreciate your patience, comments and suggestions !

Wed Jun 18, 2025 2:18 pm

Very little back pressure and separate left and right cylinders.

Even on V8 engine with true dual exhaust, they found an "X" pipe or crossover pipe helps with performance.

This style exhaust is a lot better. it has a true header and provides ground clearance for offroad use.

https://vwispwest.com/empi-classic-dune-buggy-exhaust-brushed-stainless-steel-mb3371-0/

A few years ago I built a 2180, for a customer, and this is the exhaust he wanted.

Wed Jun 18, 2025 2:49 pm

Glenn,

thanks for the clarification.

my engine has the external oil filter. So im going to try and determine if those lower pipes will hit it. I have no issue with changing to that type of exhaust, especially of it is better than what i have.

Update: I located pictures with that system mounted, and it shows that no pipes go lower than the mounting flanges! So it should work nicely. I also located a video and the sound is also not so loud as what I have.

Thank you for the information, I'll give it a try!!

Wed Jun 18, 2025 2:59 pm

Wed Jun 18, 2025 3:01 pm

Since you aren’t attached to the dune buggy duals I would look at 4 into 1 systems sold for Baja Bugs. There are options from quiet to as loud as your current dual cannons.

Since your engine is larger than stock you might look into a dual carb setup, but only after you ditch the dual exhaust. Kadrons and cannons really suck to tune, either one without the other can be just fine.

Wed Jun 18, 2025 3:12 pm

That is a better pic than the one I found, but it looks like there is plenty of clearance!

They also have a polished version that I like! I'll give it a try!!

EVfun, I'm not ready to make carb modification. Maybe eventually!

Wed Jun 18, 2025 3:42 pm

Got it ordered! I sure appreciate the guidance and the information!

Wed Jun 18, 2025 5:32 pm

Seeing as no one actually answered your question I will try to. If you look at the timing order of your engine you will see that dual cannon exhaust pairs two adjacent cylinders in the timing cycle. So what you get is a fire, fire, pause fire, fire pause on each side individually. This creates a leading and lagging cylinder much like a Harley Davidson. The cylinders do not draw equally. You have one strong cylinder and one weak cylinder on each side. This leads to a rough idle and uneven mixtures at lower engine speeds.

The end result is that you tend to get a two cylinder idle and poor torque at the low end of the RPM range. At about 3000 RPM and above things are happening fast enough that the effects disappear for the most part and there is little effect at highway speeds.

Cold startup and around town it’s a bit of a rough running dog.

Wed Jun 18, 2025 6:48 pm

awesome explanation! thanks oprn !

Thu Jun 19, 2025 2:14 am

Much the same thing happens when you put a single barrel carb on each head although not to the same degree as the exhaust. You get uneven pulses through the carbs at lower speeds. VW did it back around '66 - '67 with the type 3. We had one of those and at the time I thought VW must have used a different cam as the idle was never smooth like my Beetles were but no, that's just how dual single barrels run.

Now combine dual single carbs with dual cannons and like EVfun says, you have double the trouble!

Thu Jun 19, 2025 5:49 am

oprn, I definitely don't need any self-induced troubles :) I'm a widower and just trying to fill my time with this new hobby. I tried to buy a driver rather than a project to start with. I don't mind learning, repairing and replacing parts to make it a better driving vehicle. The learning part keeps my mind busy and is good for my soul.

I've only owned this for a couple weeks now, and the Samba community has already provided great assistance!

Thu Jun 19, 2025 7:42 am

For open back buggy and if you are looking for balanced tube length exhaust for better scavenging I suggest the TRI-MIL Bobcat...One shown is with "quiet pack muffler"....

https://aapistons.com/collections/exhaust-systems/...mic-coated

Thu Jun 19, 2025 8:43 am

oprn wrote: Seeing as no one actually answered your question I will try to. If you look at the timing order of your engine you will see that dual cannon exhaust pairs two adjacent cylinders in the timing cycle. So what you get is a fire, fire, pause fire, fire pause on each side individually. This creates a leading and lagging cylinder much like a Harley Davidson. The cylinders do not draw equally. You have one strong cylinder and one weak cylinder on each side. This leads to a rough idle and uneven mixtures at lower engine speeds.

The end result is that you tend to get a two cylinder idle and poor torque at the low end of the RPM range. At about 3000 RPM and above things are happening fast enough that the effects disappear for the most part and there is little effect at highway speeds.

Cold startup and around town it’s a bit of a rough running dog.

As Oprn stated

"So what you get is a fire, fire, pause fire, fire pause on each side individually. This creates a leading and lagging cylinder much like a Harley Davidson."

Or in the case of a VW, Two Harley Davidsons out of sink. once you get off idle and up in the rpm's does it really matter with a 34PIC T-3 Carburetor?
Other then some people just don't like the sound compared to a 4 to 1,
My build has the OG F pipes, turnarounds and some cheep chambered mufflers $19.99 each at Summit racing, I can't afford $1000.00 for a fancy setup.

It evens sounds better then a Subaru :P :P

Thu Jun 19, 2025 10:33 am

Yes I do believe you will have the same idle and low end torque issues with dual type 3 carbs and dual cannons. I would be amazed if you didn't. If you can build your own system then you could trade dollars for time. I built my dual system to pair the cylinders across from each other instead of pairing them on the same head. None of the usual idle and low end issues done that way but it took 2 1/2 days of cutting, fitting and welding...

Fri Jun 20, 2025 5:07 am

I shortened the pipe a bit and mounted a supertrap knockoff on this empi sidewinder exhaust. Its super mellow and only gets loud when i get on it hard. Engine is a 9.5:1 1904 with some decent heads

Fri Jun 20, 2025 11:28 am

I would add that glasspack mufflers tend to be on the louder side and chambered mufflers tend to be quieter. For a little 4 banger the Bug engine makes a lot of racket without a good muffler.

Fri Jun 20, 2025 1:43 pm

The HATER stinger

FTW. :twisted: